1. Field of the Invention
This invention relates to a self-holding circuit used for maintaining a relay for supplying an electric current to a controller of an automatic cruising control apparatus in an ON-state or an OFF-state.
2. Description of the Prior Art
Heretofore, there has been known a self-holding circuit housed in a controller of the automatic cruising control apparatus as a circuit for maintaining a relay in the ON-state or OFF-state in order to supply and interrupt an electric current to the controller.
In such a cruising control apparatus, by switching on a main switch of the seesaw type in an ON-state of the ignition switch, a relay coil of the relay is excited and the exciting current supply to the relay coil is maintained by the self-holding circuit. Therefore, contacts of the relay are maintained in the closed state, whereby the current supply to the controller is continued.
However, in the aforementioned conventional self-holding circuit, the seesaw type switch to be selected between an ON-state and an OFF-state is used as the main switch. Accordingly, it is not always favourable in operationality of the switch.